Methods of forming a magnetic electrode of a magnetic tunnel junction and methods of forming a magnetic tunnel junction

ABSTRACT

A method of forming a magnetic electrode of a magnetic tunnel junction comprises forming non-magnetic MgO-comprising material over conductive material of the magnetic electrode being formed. An amorphous metal is formed over the MgO-comprising material. Amorphous magnetic electrode material comprising Co and Fe is formed over the amorphous metal. The amorphous magnetic electrode material is devoid of B. Non-magnetic tunnel insulator material comprising MgO is formed directly against the amorphous magnetic electrode material. The tunnel insulator material is devoid of B. After forming the tunnel insulator material, the amorphous Co and Fe-comprising magnetic electrode material is annealed at a temperature of at least about 250° C. to form crystalline Co and Fe-comprising magnetic electrode material from an MgO-comprising surface of the tunnel insulator material. The crystalline Co and Fe-comprising magnetic electrode material is devoid of B. Other method and non-method embodiments are disclosed.

TECHNICAL FIELD

Embodiments disclosed herein pertain to magnetic tunnel junctions, tomethods of forming a magnetic electrode of a magnetic tunnel junction,and to methods of forming a magnetic tunnel junction.

BACKGROUND

A magnetic tunnel junction is an integrated circuit component having twoconductive magnetic electrodes separated by a thin non-magnetic tunnelinsulator material (e.g., dielectric material). The insulator materialis sufficiently thin such that electrons can tunnel from one magneticelectrode to the other through the insulator material under appropriateconditions. At least one of the magnetic electrodes can have its overallmagnetization direction switched between two states at a normaloperating write or erase current/voltage, and is commonly referred to asthe “free” or “recording” electrode. The other magnetic electrode iscommonly referred to as the “reference”, “fixed”, or “pinned” electrode,and whose overall magnetization direction will not switch uponapplication of the normal operating write or erase current/voltage. Thereference electrode and the recording electrode are electrically coupledto respective conductive nodes. The resistance of current flow betweenthose two nodes through the reference electrode, insulator material, andthe recording electrode is dependent upon the overall magnetizationdirection of the recording electrode relative to that of the referenceelectrode. Accordingly, a magnetic tunnel junction can be programmedinto one of at least two states, and those states can be sensed bymeasuring current flow through the magnetic tunnel junction. Sincemagnetic tunnel junctions can be “programmed” between twocurrent-conducting states, they have been proposed for use in memoryintegrated circuitry. Additionally, magnetic tunnel junctions may beused in logic or other circuitry apart from or in addition to memory.

The overall magnetization direction of the recording electrode can beswitched by a current-induced external magnetic field or by using aspin-polarized current to result in a spin-transfer torque (STT) effect.Charge carriers (such as electrons) have a property known as “spin”which is a small quantity of angular momentum intrinsic to the carrier.An electric current is generally unpolarized (having about 50% “spin-up”and about 50% “spin-down” electrons). A spin-polarized current is onewith significantly more electrons of either spin. By passing a currentthrough certain magnetic material (sometimes also referred to aspolarizer material), one can produce a spin-polarized current. If aspin-polarized current is directed into a magnetic material, spinangular momentum can be transferred to that material, thereby affectingits magnetization orientation. This can be used to excite oscillationsor even flip (i.e., switch) the orientation/domain direction of themagnetic material if the spin-polarized current is of sufficientmagnitude.

An alloy or other mixture of Co and Fe is one common material proposedfor use as a polarizer material and/or as at least part of the magneticrecording material of a recording electrode in a magnetic tunneljunction. A more specific example is Co_(x)Fe_(y)B_(z) where x and y areeach 10-80 and z is 0-50, and may be abbreviated as CoFe or CoFeB. MgOis an ideal material for the non-magnetic tunnel insulator. Ideally suchmaterials are each crystalline having a body-centered-cubic (bcc) 001lattice. Such materials may be deposited using any suitable technique,for example by physical vapor deposition. One technique usable toultimately produce the bcc 001 lattice in such materials includesinitially forming CoFe to be amorphous and upon which MgO-comprisingtunnel insulator material is deposited. During and/or after thedepositing, the MgO tunnel insulator, the CoFe, and the tunnel insulatorideally individually achieve a uniform bcc 001 lattice structure.

Boron is commonly deposited as part of the CoFe to assure or provide

initial amorphous deposition of the CoFe. Crystallization of the CoFecan occur during or after deposition of the MgO by annealing thesubstrate at a temperature of at least about 350° C. This will inducethe diffusion of B atoms out of the CoFe matrix being formed to allowcrystallization into bcc 001 CoFe. Bcc 001 MgO acts as a template duringthe crystallization of CoFe. However, B in the finished magnetic tunneljunction construction, specifically at the CoFe/MgO interface or insidethe MgO lattice, undesirably reduces tunneling magnetoresistance (TMR)of the magnetic tunnel junction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic sectional view of a substrate fragment.

FIG. 2 is a diagrammatic sectional view of a substrate fragment.

FIG. 3 is a diagrammatic sectional view of substrate fragment in processin the fabrication of a magnetic tunnel junction in accordance with anembodiment of the invention.

FIG. 4 is a view of the FIG. 3 substrate fragment at a processing stepsubsequent to that shown by FIG. 3.

FIG. 5 is a view of the FIG. 4 substrate fragment at a processing stepsubsequent to that shown by FIG. 4.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Embodiments of the invention encompass methods of forming a magneticelectrode of a magnetic tunnel junction and methods of forming amagnetic tunnel junction. Additionally, embodiments of the inventionencompass magnetic tunnel junctions independent of method ofmanufacture. Example methods in accordance with some embodiments of theinvention are initially described with reference to FIG. 1 with respectto a substrate fragment 10, and which may comprise a semiconductorsubstrate. In the context of this document, the term “semiconductorsubstrate” or “semiconductive substrate” is defined to mean anyconstruction comprising semiconductive material, including, but notlimited to, bulk semiconductive materials such as a semiconductive wafer(either alone or in assemblies comprising other materials thereon), andsemiconductive material layers (either alone or in assemblies comprisingother materials). The term “substrate” refers to any supportingstructure, including, but not limited to, the semiconductive substratesdescribed above. Substrate fragment 10 comprises a base or substrate 11showing various materials having been formed as an elevational stackthere-over. Materials may be aside, elevationally inward, orelevationally outward of the FIG. 1-depicted materials. For example,other partially or wholly fabricated components of integrated circuitrymay be provided somewhere about or within fragment 10. Substrate 11 maycomprise any one or more of conductive (i.e., electrically herein),semiconductive, or insulative/insulator (i.e., electrically herein)material(s). Regardless, any of the materials, regions, and structuresdescribed herein may be homogenous or non-homogenous, and regardless maybe continuous or discontinuous over any material which such overlie.Further, unless otherwise stated, each material may be formed using anysuitable or yet-to-be-developed technique, with atomic layer deposition,chemical vapor deposition, physical vapor deposition, epitaxial growth,diffusion doping, and ion implanting being examples.

Conductive material 12 of a magnetic (i.e., ferrimagnetic orferromagnetic herein) electrode material that is being formed is formedover substrate 11. Any conductive material may be used, such as one ormore elemental metal(s), an alloy of two or more elemental metals,conductively doped semiconductive material, and conductive metalcompounds. In one embodiment, conductive material 12 is non-magnetic.One specific example material 12 is elemental tantalum. An examplemaximum thickness for conductive material 12 is about 5 Angstroms toabout 500 Angstroms. In this document, “thickness” by itself (nopreceding directional adjective) is defined as the mean straight-linedistance through a given material or region perpendicularly from aclosest surface of an immediately adjacent material of differentcomposition or of an immediately adjacent region. Additionally, thevarious materials or regions described herein may be of substantiallyconstant thickness or of variable thicknesses. If of variable thickness,thickness refers to average thickness unless otherwise indicated. Asused herein, “different composition” only requires those portions of twostated materials or regions that may be directly against one another tobe chemically and/or physically different, for example if such materialsor regions are not homogenous. If the two stated materials or regionsare not directly against one another, “different composition” onlyrequires that those portions of the two stated materials ore regionsthat are closest to one another be chemically and/or physicallydifferent if such materials or regions are not homogenous. In thisdocument, a material, region, or structure is “directly against” anotherwhen there is at least some physical touching contact of the statedmaterials, regions, or structures relative one another. In contrast,“over”, “on”, and “against” not preceded by “directly” encompass“directly against” as well as construction where interveningmaterial(s), region(s), or structure(s) result(s) in no physicaltouching contact of the stated materials, regions, or structuresrelative one another.

Material 14 comprising Co, Fe, and B is formed over conductive material12. In one embodiment, material 14 comprises an alloy of Co and Fe, withamorphous Co₄₀Fe₄₀B₂₀ being an example. Characterization of a materialor region as being “amorphous” where used in this document requires atleast 90% by volume of the stated material to be amorphous. An examplemaximum thickness for material 14 when used is about 2 Angstroms toabout 6 Angstroms.

Non-magnetic MgO-comprising material 16 is formed over conductivematerial 12 (regardless of presence of material 14). Material 16 maycomprise, consist essentially of, or consist of MgO. An example maximumthickness for MgO-comprising material 16 is about 3 Angstroms to about10 Angstroms. A purpose for including material 14 is to facilitateforming bcc 001 MgO during its deposition. A purpose for includingmaterial 16 is to facilitate perpendicular magnetic anisotropy inmagnetic material of the conductive magnetic electrode being formed,which is a desirable operational trait of some magnetic tunneljunctions.

Amorphous metal 18 is formed over MgO-comprising material 16, and in oneembodiment, as shown, is formed directly against MgO-comprising material16. In one embodiment, amorphous metal 18 comprises an alloy oftransition metals, and in one embodiment consists essentially of orconsists of an alloy of transition metals. In one embodiment, amorphousmetal 18 comprises an alloy comprising Fe, Co, and another transitionmetal. In one embodiment, amorphous metal 18 comprises an alloy of atleast one of Hf, Zr, W, Mo, Al, Cr, and Ta and at least one of Fe, Co,and Ni. In one embodiment, amorphous metal 18 comprises a W alloy, forexample any one or more of Fe, Co, and Ni alloyed with W. In oneembodiment, amorphous metal 18 has a maximum thickness of about 3Angstroms to about 5 Angstroms.

Amorphous magnetic electrode material 20 comprising Co and Fe is formedover, and in one embodiment directly against, amorphous metal 18.Amorphous magnetic electrode material 20 is devoid of B. In thisdocument, “devoid of B” means 0 atomic % B to no more than 0.1 atomic %B. Reference to “magnetic” herein does not require a stated magneticmaterial ore region to be magnetic as initially formed, but does requiresome portion of the stated magnetic material or region to befunctionally “magnetic” in a finished circuit construction of themagnetic tunnel junction. In one embodiment, the Co and Fe of amorphousmagnetic electrode material 20 are formed directly against amorphousmetal 18. In one embodiment, amorphous magnetic electrode material 20 isformed at a temperature of 0° C. to about 30° C., and in one suchembodiment at a temperature of at least about 20° C. In one embodiment,amorphous magnetic electrode material 20 is formed at a temperature ofabout −250° C. to less than 0° C., and in one such embodiment at atemperature of about −250° C. to about −20° C. Formation of electrodematerial 20 below 30° C., and ideally below 0° C., facilitates amorphousformation of such material when it is devoid of B and amorphous metal 18is present. An example maximum thickness for material 20 is about 7Angstroms to about 15 Angstroms.

Non-magnetic tunnel insulator material 22 comprising MgO is formeddirectly against amorphous magnetic electrode material 20. Tunnelinsulator material 22 is devoid of B. Non-magnetic tunnel insulatormaterial 22 may comprise, consist essentially of, or consist of MgO. Anexample maximum thickness for tunnel insulator material 22 is about 5Angstroms to about 25 Angstroms.

Materials 12, 14, 16, 18, and 20 will collectively be used to ultimatelyform a conductive magnetic electrode 25 of the magnetic tunnel junctionbeing formed. Material 24 is shown as being formed outwardly of tunnelinsulator material 22, and in one embodiment directly against material22, and will ultimately be used in forming another conductive magneticelectrode 27 of the magnetic tunnel junction being formed. One ofelectrodes 25 and 27 will be configured to comprise magnetic recordingmaterial while the other of electrodes 25 and 27 will be configured tocomprise magnetic reference material. Electrodes 25 and 27 individuallymay contain non-magnetic insulator, semiconductive, and/or conductivematerial or regions. However, electrodes 25 and 27 when consideredindividually are characterized as being overall and collectivelymagnetic and conductive even though the electrode may have one or moreregions therein that are intrinsically locally non-magnetic and/ornon-conductive. An example maximum thickness for electrode 27 is about20 Angstroms to about 150 Angstroms. As but one example, material 24comprises 13 Angstroms of Co₄₀Fe₄₀B₂₀ directly against tunnel insulatormaterial 22, 3 Angstroms of Ta directly against the Co₄₀Fe₄₀B_(20,) and40 Angstroms of an alloy/multilayer of Co with Pd/Pt directly againstthe Ta, with electrode 27 in such example functioning as the magneticreference electrode. Such materials collectively in such exampleconstitute magnetic reference material thereof. Electrode 25 in suchexample functions as the magnetic recording electrode with, for example,material 20 upon crystallization ultimately functioning as the magneticrecording material.

After forming tunnel insulator material 22, amorphous Co andFe-comprising magnetic electrode material 20 is annealed at atemperature of at least about 250° C. (e.g., in an inert atmosphere) toform crystalline Co and Fe-comprising magnetic electrode material 20from an MgO-comprising surface of tunnel insulator material 22 (e.g.,from a surface 23). Crystalline Co and Fe-comprising magnetic electrodematerial 20 is devoid of B. An example preferred upper temperature limitfor the annealing is 450° C. Characterization of a material or region asbeing “crystalline” where used in this document requires at least 90% byvolume of the stated material or region to be crystalline. In oneembodiment, crystalline Co and Fe-comprising magnetic electrode material20 has a maximum thickness of about 7 Angstroms to about 15 Angstroms.

Materials 12, 14, 16, 18, 20, 22, and 24 may be blanketly formed over asubstrate 11 followed by collective patterning thereof to form a desiredfinished circuit construction of the magnetic tunnel junction beingformed. Alternately, patterning of one or more such materials may occurbefore, during, or after any such materials are formed over substrate11, and/or before, during, or after any annealing. Regardless, in oneembodiment, conductive magnetic electrode 25 comprises magneticrecording material (e.g., crystalline Co and Fe-comprising material 20)and conductive magnetic electrode 27 comprises magnetic referencematerial. Additionally or alternately considered, the elevationalpositions of electrodes 25 and 27 may be reversed and/or an orientationother than an elevational stack may be used (e.g., lateral; diagonal; acombination of one or more of elevational, horizontal, diagonal; etc.).In this document, “elevational”, “upper”, “lower”, “top”, and “bottom”are with reference to the vertical direction. “Horizontal” refers to ageneral direction along a primary surface relative to which thesubstrate is processed during fabrication, and vertical is a directiongenerally orthogonal thereto. Further, “vertical” and “horizontal” asused herein are generally perpendicular directions relative one anotherand independent of orientation of the substrate in three-dimensionalspace.

Another embodiment method of forming a magnetic electrode of a magnetictunnel junction is next described with reference to FIG. 2 with respectto a substrate fragment 10 a. Like numerals from the above-describedembodiments have been used where appropriate, with some constructiondifferences being indicated with the suffix “a”. Amorphous metal 18 a isformed over substrate 11 (regardless of presence of conductive material12 or other material). In one embodiment and as shown, amorphous metal18 a is formed directly against other physically and/or chemicallydifferent conductive material 12 of the magnetic electrode 25 a beingformed. In one embodiment, amorphous metal 18 a has a maximum thicknessof about 10 Angstroms to about 100 Angstroms.

Amorphous magnetic electrode material 20 comprising Co and Fe (and thatis devoid of B) is formed over amorphous metal 18 a at a temperature ofabout −250° C. to about 30° C. In one embodiment, amorphous magneticelectrode material 20 a is formed at a temperature of 0° C. to about 30°C. In one embodiment, amorphous magnetic electrode material 20 is formedat a temperature of about −250° C. to less than about 0° C., and in oneembodiment to less than about −20° C.

Non-magnetic tunnel insulator material 22 comprising MgO (and that isdevoid of B) is formed directly against amorphous magnetic electrodematerial 20. After forming tunnel insulator material 22, amorphous Coand Fe-comprising magnetic electrode material 20 is annealed at atemperature of at least about 250° C. to form crystalline Co andFe-comprising magnetic electrode material 20 (and that is devoid of B)from an MgO-comprising surface of tunnel insulator material 22 (e.g.,from surface 23). Any other attribute(s) or aspect(s) as described aboveand/or shown in FIG. 1 may be used in the FIG. 2 embodiments.

Methods of forming a magnetic tunnel junction in accordance with someembodiments of the invention are next described beginning with referenceto FIG. 3 with respect to a substrate fragment 10 b. Like numerals fromthe above-described embodiments have been used where appropriate, withsome construction differences being indicated with the suffix “b” orwith different numerals. Inner magnetic electrode material 25 b isformed over substrate 11. Electrode 25 b may comprise any one or more ofmaterials 12, 14, 16, 18/18 a, and 20 (not shown) as in theabove-described embodiments, and/or additional or other material(s), andmay be formed using any of the above-described or other process(es).Non-magnetic tunnel insulator material 22 comprising MgO (and that isdevoid of B) is formed over inner magnetic electrode material 25 b.

After forming tunnel insulator material 22, it is annealed at atemperature of at least about 250° C., and in one embodiment at about300° C. to about 550° C. Such may be conducted to induce crystallizationof MgO of tunnel insulator material 22 and/or to produce desired uniformcrystallization therein, such as bcc 001 lattice orientation.

Referring to FIG. 4, after the annealing and in one embodiment, outercrystalline magnetic electrode material 30 is formed at a temperature ofat least about 150° C. (and in one embodiment at less than about 250°C.) from an MgO-comprising surface of annealed tunnel insulator material22 (e.g., from a surface 29). Outer crystalline magnetic electrodematerial 30 comprises Co and Fe and is devoid of B. Any of theabove-described Co and Fe-comprising materials (that are devoid of B)may be used.

In one alternate embodiment after the annealing of tunnel insulatormaterial 22, an outer amorphous magnetic electrode material 30 is formedat a temperature of about −250° C. to less than about 0° C. directlyagainst annealed tunnel insulator material 22. Such outer amorphousmagnetic electrode material 30 comprises Co and Fe and is devoid of B.It is subsequently annealed at a temperature of at least about 250° C.to form outer crystalline Co and Fe-comprising magnetic electrodematerial 30 (and that is devoid of B) from an MgO-comprising surface ofannealed tunnel insulator material 22 (e.g., surface 29). In oneembodiment, the Co and Fe of outer amorphous magnetic electrode material30 are formed directly against annealed tunnel insulator material 22 ata temperature less than or equal to about −20° C. In one embodiment, theannealing to form outer crystalline magnetic electrode material 30 isconducted at a temperature of at least about 300° C., and in oneembodiment at a temperature of no greater than about 400° C.

Referring to FIG. 5, additional material 24 b is deposited over outercrystalline magnetic electrode material 30 to comprise part ofconductive magnetic electrode 27 b. In one embodiment, outer crystallinemagnetic electrode material 30 has a maximum thickness of about 5Angstroms to about 15 Angstroms. Any other attribute(s) or aspect(s) asdescribed above and/or shown in FIGS. 1 and 2 may be used in the FIGS.3-5 embodiments.

Embodiments of the invention encompass a magnetic electrode of amagnetic tunnel junction manufactured in accordance with any of theabove descriptions. Embodiments of the invention also encompass amagnetic tunnel junction manufactured in accordance with any of theabove descriptions.

Further, embodiments of the invention encompass magnetic tunneljunctions independent of the method of manufacture, and the discussionso proceeds and concludes. Such embodiments comprise a conductive firstmagnetic electrode comprising magnetic recording material and aconductive second magnetic electrode comprising magnetic referencematerial spaced from the first electrode. Example electrodes 25, 25 a,25 b, 27, and 27 b as described above may comprise such first or secondsuch electrodes. Alternately or additionally considered, when themagnetic tunnel junction is fabricated as a stack of materials, eitherthe elevationally outer or elevationally inner electrode may comprisemagnetic recording material or magnetic reference material. Regardless,a non-magnetic tunnel insulator material comprising MgO (e.g., tunnelinsulator material 22) is between the first and second electrodes. Thetunnel insulator is devoid of B. In one embodiment, the non-magnetictunnel insulator material has a maximum thickness of no greater thanabout 20 Angstroms.

In one embodiment, at least one of the magnetic recording material andthe magnetic reference material comprises a crystalline magnetic regionthat comprises Co and Fe and that is devoid of B, with such regionhaving a maximum thickness of no greater than about 30 Angstroms, in oneembodiment that is no greater than about 20 Angstroms, and in oneembodiment that is no greater than about 15 Angstroms. Co and Fe of suchcrystalline magnetic region are directly against MgO of the tunnelinsulator. As examples, component 20 and/or 30 (if devoid of B) maycomprise such a crystalline magnetic region of magnetic recordingmaterial or magnetic reference material that is part of one of electrode25/25 a/25 b or electrode 27/27 b. In one embodiment, both the magneticrecording material and the magnetic reference material have acrystalline magnetic region that comprises Co and Fe that is devoid of Band that is directly against MgO of the tunnel insulator material andhaving a maximum thickness of no greater than about 30 Angstroms. Anyother attribute(s) or aspect(s) as described above and/or shown in theFigures may be used.

In one embodiment, the non-magnetic tunnel insulator material comprisingMgO has a maximum thickness of no greater than about 20 Angstroms. Themagnetic recording material and the magnetic reference material of thefirst and second electrodes each comprise a respective crystallinemagnetic region comprising Co and Fe that is devoid of B and has amaximum thickness of no greater than about 30 Angstroms regardless ofwhether Co and Fe of such crystalline magnetic region is directlyagainst MgO of the tunnel insulator material. In one embodiment, the Coand Fe-comprising crystalline magnetic regions that are devoid of B havea respective maximum thickness of no greater than about 20 Angstroms,and in one embodiment no greater than about 15 Angstroms. In oneembodiment, the Co and Fe-comprising crystalline magnetic region that isdevoid of B of the second electrode has a maximum thickness that isgreater than that of the first electrode. Any other attribute(s) oraspect(s) as described above and/or shown in the Figures may be used.

In one embodiment, the magnetic recording material or the magneticreference material of at least one of the first and second electrodescomprises a crystalline magnetic region that comprises Co and Fe andthat is devoid of B (e.g., material 20). In one such embodiment, suchregion has a maximum thickness that is no greater than about 20Angstroms. Such at least one of the first and second electrodes alsocomprises a non-magnetic MgO-comprising region (e.g., material 16) andan amorphous metal region (e.g., material 18). The Co and Fe-comprisingmagnetic region that is devoid of B (e.g., material 20) is between thetunnel insulator material (e.g., material 22) and the MgO-comprisingregion (e.g., material 16). The amorphous metal region (e.g., material18) is between the MgO-comprising region (e.g., material 16) and the Coand Fe-comprising magnetic region that is devoid of B (e.g., material20). In one such embodiment, the MgO-comprising region has a maximumthickness of about 3 Angstroms to about 10 Angstroms. In one embodiment,the amorphous metal region has a maximum thickness of about 3 Angstromsto about 5 Angstroms. In one embodiment, the Co and Fe of thecrystalline magnetic region are directly against MgO of the tunnelinsulator material, and in one embodiment are directly against theamorphous metal region. In one embodiment, the amorphous metal region isdirectly against MgO of the MgO-comprising region. In one embodiment,the at least one of the first and second electrodes comprises anotherregion comprising Co, Fe, and B (e.g., material 14). In one embodiment,the another region has a maximum thickness less than about 10 Angstroms.In one embodiment, the Co, Fe, and B of the another region are directlyagainst MgO of the MgO-comprising region. Any other attribute(s) oraspect(s) as described above and/or shown in the Figures may be used.

In one embodiment, the magnetic recording material or the magneticreference material of at least one of the first and second electrodescomprises a crystalline magnetic region that comprises Co and Fe andthat is devoid of B (e.g., material 20 or material 30 when devoid of B).Such at least one of the first and second electrodes comprisesconductive material (e.g., material 12) and an amorphous metal region(e.g., material 18/18 a) different from the conductive material. The Coand Fe-comprising crystalline magnetic region that is devoid of B (e.g.,material 20) is between the tunnel insulator material (e.g., material22) and the conductive material (e.g., material 12). The amorphous metalregion (e.g., material 18/18 a) is between the conductive material(e.g., material 12) and the Co and Fe-comprising crystalline magneticregion that is devoid of B (e.g., material 20). In one embodiment, theCo and Fe of the crystalline magnetic region are directly against theamorphous metal region, and in one embodiment are directly against MgOof the tunnel insulator material. In one embodiment, the amorphous metalregion is directly against the conductive material, and in oneembodiment has a maximum thickness of about 10 Angstroms to about 100Angstroms. In one embodiment, the crystalline magnetic region has amaximum thickness of about 7 Angstroms to about 15 Angstroms. Any otherattribute(s) or aspect(s) as described above and/or shown in the Figuresmay be used.

In one embodiment, the magnetic recording material and the magneticreference material of the first and second electrodes comprise arespective crystalline magnetic region that is directly against MgO ofthe tunnel insulator material (e.g., material 20 and material 30). Thecrystalline magnetic region of at least one of the first and secondelectrodes comprises Co and Fe and is devoid of B. Such at least one ofthe first and second electrodes that comprises the Co and Fe-comprisingcrystalline magnetic region that is devoid of B comprises conductivematerial (e.g., material 12) and an amorphous metal region (e.g.,material 18/18 a) different from the conductive material. The Co andFe-comprising crystalline magnetic region that is devoid of B (e.g.,material 20) is between the tunnel insulator material (e.g., material22) and the conductive material (e.g., material 12), and has a maximumthickness of no greater than about 30 Angstroms. The amorphous metalregion (e.g., material 18/18 a) is between the conductive material(e.g., material 12) and the Co and Fe-comprising crystalline magneticregion that is devoid of B (e.g., material 20) and has a maximumthickness no greater than about 100 Angstroms. Any other attribute(s) oraspect(s) as described above and/or shown in the Figures may be used.

Each of the above-described magnetic tunnel junction structureembodiments that are independent of method of manufacture mayincorporate any of the structural features or attributes shown and/ordescribed above with respect to the method embodiments, and of coursecan be manufactured using any aspect(s) or attribute(s) of such methodembodiments.

The example embodiments of FIGS. 1-4 depict single magnetic tunneljunctions (SMTJs). However, dual magnetic tunnel junctions (DMTJs) ormore than dual (two) magnetic tunnel junctions are contemplated

CONCLUSION

In some embodiments, a method of forming a magnetic electrode of amagnetic tunnel junction comprises forming non-magnetic MgO-comprisingmaterial over conductive material of the magnetic electrode beingformed. An amorphous metal is formed over the MgO-comprising material.Amorphous magnetic electrode material comprising Co and Fe is formedover the amorphous metal. The amorphous magnetic electrode material isdevoid of B. Non-magnetic tunnel insulator material comprising MgO isformed directly against the amorphous magnetic electrode material. Thetunnel insulator material is devoid of B. After forming the tunnelinsulator material, the amorphous Co and Fe-comprising magneticelectrode material is annealed at a temperature of at least about 250°C. to form crystalline Co and Fe-comprising magnetic electrode materialfrom an MgO-comprising surface of the tunnel insulator material. Thecrystalline Co and Fe-comprising magnetic electrode material is devoidof B.

In some embodiments, a method of forming a magnetic electrode of amagnetic tunnel junction comprises forming amorphous metal over asubstrate. Amorphous magnetic electrode material comprising Co and Fe isformed over the amorphous metal at a temperature of about −250° C. toabout 30° C. The amorphous magnetic electrode material is devoid of B.Non-magnetic tunnel insulator material comprising MgO is formed directlyagainst the amorphous magnetic electrode material. The tunnel insulatormaterial is devoid of B. After forming the tunnel insulator material,the amorphous Co and Fe-comprising magnetic electrode material isannealed at a temperature of at least about 250° C. to form crystallineCo and Fe-comprising magnetic electrode material from an MgO-comprisingsurface of the tunnel insulator material. The crystalline Co andFe-comprising magnetic electrode material is devoid of B.

In some embodiments, a method of forming a magnetic tunnel junctioncomprises forming inner magnetic electrode material over a substrate.Non-magnetic tunnel insulator material comprising MgO is formed over theinner magnetic electrode material. The tunnel insulator material isdevoid of B. After forming the tunnel insulator material, the tunnelinsulator material is annealed at a temperature of at least about 250°C. After the annealing, outer crystalline magnetic electrode material isformed at a temperature of at least about 150° C. from an MgO-comprisingsurface of the annealed tunnel insulator material. The outer crystallinemagnetic electrode material comprises Co and Fe and is devoid of B.

In some embodiments, a method of forming a magnetic tunnel junctioncomprises forming inner magnetic electrode material over a substrate.Non-magnetic tunnel insulator material comprising MgO is formed over theinner magnetic electrode material. The tunnel insulator material isdevoid of B. After forming the tunnel insulator material, the tunnelinsulator material is annealed at a temperature of at least about 250°C. After the annealing of the tunnel insulator material, outer amorphousmagnetic electrode material is formed at a temperature of about −250° C.to less than 0° C. directly against the annealed tunnel insulatormaterial. The outer amorphous magnetic electrode material comprises Coand Fe that is directly against the annealed tunnel insulator materialand which is devoid of B. The outer amorphous Co and Fe-comprisingmagnetic electrode material is annealed at a temperature of at leastabout 250° C. to form outer crystalline Co and Fe-comprising magneticelectrode material from an MgO-comprising surface of the annealed tunnelinsulator material. The crystalline Co and Fe-comprising outer magneticelectrode material is devoid of B.

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording material. Aconductive second magnetic electrode is spaced from the first electrodeand comprises magnetic reference material. A non-magnetic tunnelinsulator material comprising MgO is between the first and secondelectrodes. The tunnel insulator material is devoid of B and has amaximum thickness that is no greater than about 20 Angstroms. At leastone of the magnetic recording material and the magnetic referencematerial comprises a crystalline magnetic region that comprises Co andFe and that is devoid of B. The Co and Fe-comprising crystallinemagnetic region that is devoid of B has a maximum thickness of nogreater than about 30 Angstroms. Co and Fe of the crystalline magneticregion are directly against MgO of the tunnel insulator material.

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording material. Aconductive second magnetic electrode is spaced from the first electrodeand comprises magnetic reference material. A non-magnetic tunnelinsulator material comprising MgO is between the first and secondelectrodes. The tunnel insulator is devoid of B and has a maximumthickness that is no greater than about 20 Angstroms. The magneticrecording material and the magnetic reference material of the first andsecond electrodes each comprises a respective crystalline magneticregion comprising Co and Fe that is devoid of B, and having a maximumthickness of no greater than about 30 Angstroms.

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording material. Aconductive second magnetic electrode is spaced from the first electrodeand comprises magnetic reference material. A non-magnetic tunnelinsulator material comprising MgO is between the first and secondelectrodes. The tunnel insulator material is devoid of B. The magneticrecording material or the magnetic reference material of at least one ofthe first and second electrodes comprises a crystalline magnetic regionthat comprises Co and Fe and that is devoid of B. The at least one ofthe first and second electrodes comprises a non-magnetic MgO-comprisingregion and an amorphous metal region. The Co and Fe-comprisingcrystalline magnetic region that is devoid of B is between the tunnelinsulator material and the MgO-comprising region. The amorphous metalregion is between the MgO-comprising region and the Co and Fe-comprisingcrystalline magnetic region that is devoid of B.

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording material. Aconductive second magnetic electrode is spaced from the first electrodeand comprises magnetic reference material. A non-magnetic tunnelinsulator material comprising MgO is between the first and secondelectrodes. The tunnel insulator material is devoid of B. The magneticrecording material or the magnetic reference material of at least one ofthe first and second electrodes comprises a crystalline magnetic regionthat comprises Co and Fe and that is devoid of B. The at least one ofthe first and second electrodes comprises conductive material and anamorphous metal region different from the conductive material. The Coand Fe-comprising crystalline magnetic region that is devoid of B isbetween the tunnel insulator material and the conductive material. Theamorphous metal region is between the conductive material and the Co andFe-comprising region that is devoid of B.

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording material. Aconductive second magnetic electrode is spaced from the first electrodeand comprises magnetic reference material. A non-magnetic tunnelinsulator material comprising MgO is between the first and secondelectrodes. The tunnel insulator material is devoid of B. The magneticrecording material and the magnetic reference material of the first andsecond electrodes comprise a respective crystalline magnetic region thatis directly against MgO of the tunnel insulator material. Thecrystalline magnetic region of at least one of the first and secondelectrodes comprises Co and Fe and is devoid of B. The at least one ofthe first and second electrodes that comprises the Co and Fe-comprisingcrystalline magnetic region that is devoid of B comprises conductivematerial and an amorphous metal region different from the conductivematerial. The Co and Fe-comprising crystalline magnetic region that isdevoid of B is between the tunnel insulator material and the conductivematerial and has a maximum thickness no greater than about 30 Angstroms.The amorphous metal region is between the conductive material and the Coand Fe-comprising crystalline magnetic region that is devoid of B andhas a maximum thickness no greater than about 100 Angstroms.

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

1. A method of forming a magnetic electrode of a magnetic tunneljunction, comprising: forming non-magnetic MgO-comprising material overconductive material of the magnetic electrode being formed; formingamorphous metal over the MgO-comprising material, the amorphous metalcomprising an alloy of a) at least one of Mo and Cr, and at least one ofFe, Co, and Ni, or b) Al and Ni; forming amorphous magnetic electrodematerial comprising Co and Fe over the amorphous metal, the amorphousmagnetic electrode material being devoid of B; forming non-magnetictunnel insulator material comprising MgO directly against the amorphousmagnetic electrode material, the tunnel insulator material being devoidof B; and after forming the tunnel insulator material annealing theamorphous Co and Fe-comprising magnetic electrode material at atemperature of at least 250° C. to form crystalline Co and Fe-comprisingmagnetic electrode material from an MgO-comprising surface of the tunnelinsulator material, the crystalline Co and Fe-comprising magneticelectrode material being devoid of B.
 2. The method of claim 1comprising forming a material comprising Co, Fe, and B, over theconductive material; and forming the MgO-comprising material over thematerial comprising Co, Fe, and B. 3-5. (canceled)
 6. The method ofclaim 1 wherein the Co and Fe of the amorphous magnetic electrodematerial are formed directly against the amorphous metal.
 7. The methodof claim 1 wherein the amorphous magnetic electrode material is formedat a temperature of 0° C. to 30° C.
 8. The method of claim 7 wherein theamorphous magnetic electrode material is formed at a temperature of atleast 20° C.
 9. The method of claim 1 wherein the amorphous magneticelectrode material is formed at a temperature of 250° C. to less than 0°C.
 10. The method of claim 9 wherein the amorphous magnetic electrodematerial is formed at a temperature of 250° C. to −20° C.
 11. The methodof claim 1 wherein the amorphous metal has a maximum thickness of 3Angstroms to 5 Angstroms.
 12. The method of claim 1 wherein thecrystalline Co and Fe-comprising magnetic electrode material has amaximum thickness of 7 Angstroms to 15 Angstroms.
 13. A magnetic tunneljunction incorporating the magnetic electrode produced using the methodof claim
 1. 14. A method of forming a magnetic electrode of a magnetictunnel junction, comprising: forming amorphous metal over a substrate,the amorphous metal comprising an a Hoy of a) at least one of Mo and Cr,and at least one of Fe, Co, and Ni, or b) Al and Ni; forming amorphousmagnetic electrode material comprising Co and Fe over the amorphousmetal at a temperature of −250° C.; to 30° C., the amorphous magneticelectrode material being devoid of B; forming non-magnetic tunnelinsulator material comprising MgO directly against the amorphousmagnetic electrode material, the tunnel insulator material being devoidof B; and after forming the tunnel insulator material, annealing theamorphous Co and Fe-comprising magnetic electrode material at atemperature of at least 250° C. to form crystalline Co and Fe-comprisingmagnetic electrode material from an MgO-comprising surface of the tunnelinsulator material, the crystalline Co and Fe-comprising magneticelectrode material being devoid of B.
 15. The method of claim 14 whereinthe Co and Fe of the amorphous magnetic electrode material are formeddirectly against the amorphous metal.
 16. The method of claim 14 whereinthe amorphous metal is formed directly against other physically and/orchemically different conductive material of the magnetic electrode beingformed.
 17. The method of claim 14 wherein, the Co and Fe of theamorphous magnetic electrode material are formed directly against theamorphous metal; and the amorphous metal is formed directly againstother physically and/or chemically different conductive material of themagnetic electrode being formed.
 18. The method of claim 14 wherein theamorphous metal has a maximum thickness of 10 Angstroms to 100Angstroms.
 19. The method of claim 14 wherein the amorphous magneticelectrode material is formed at a temperature of 0° C. to 30° C.
 20. Themethod of claim 14 wherein the amorphous magnetic electrode material isformed at a temperature of 250° C. to less than 0° C.
 21. The method ofclaim 14 wherein the amorphous metal comprises an alloy of transitionmetals.
 22. The method of claim 21 wherein the amorphous metal consistsessentially of an alloy of transition metals.
 23. A magnetic tunneljunction in corpora ting the magnetic electrode produced using themethod of claim
 14. 24-40. (canceled)
 41. The method of claim 1 whereinthe amorphous metal comprises an alloy of Al and Ni.
 42. The method ofclaim 1 wherein the amorphous metal comprises an alloy of Mo and atleast one of Fe, Co, and Ni.
 43. The method of claim 1 wherein theamorphous metal comprises an alloy of Cr and at least one of Fe, Co, andNi.
 44. The method of claim 1 wherein the amorphous metal comprises analloy comprising at least one of Mo and Cr, and Fe.
 45. The method ofclaim 1 wherein the amorphous metal comprises an alloy comprising atleast one of Mo and Cr, and Co.
 46. The method of claim 1 wherein theamorphous metal comprises an alloy comprising at least one of Mo and Cr,and Ni.
 47. The method of claim 1 wherein the amorphous metal comprisesan alloy comprising Mo and Cr.
 48. The method of claim 14 wherein theamorphous metal comprises an alloy of Al and Ni.
 49. The method of claim14 wherein the amorphous metal comprises an alloy of Mo and at least oneof Fe, Co, and Ni.
 50. The method of claim 14 wherein the amorphousmetal comprises an allow of Cr and at least one of Fe, Co, and Ni. 51.The method of claim 14 wherein the amorphous metal comprises an allowcomprising at least one of Mo and Cr, and Fe.
 52. The method of claim 14wherein the amorphous metal comprises an allow comprising at least oneof Mo and Cr, and Co.
 53. The method of claim 14 wherein the amorphousmetal comprises an allow comprising at least one of Mo and Cr, and Ni.54. The method of claim 14 wherein the amorphous metal comprises anallow comprising Mo and Cr.